Taxonomic and non-taxonomic responses of benthic macroinvertebrates to metal toxicity in tropical reservoirs. The case of Cantareira Complex, São Paulo, Brazil.

Benthic macroinvertebrates are organisms that are recognized as water quality bio-indicators. A wide variety of indices and metrics have been shown to respond to a variety of anthropogenic impacts, usually under a general condition of environmental impairment. The absence of a clear distinction in the relations between specific pollutants and biotic variables is very common and can lead to biased interpretation of biomonitoring. The aims of this research were to test taxonomic and non-taxonomic responses to specific environmental conditions instead to general conditions. For this purpose, we estimated the theoretical toxicity by comparing toxicity values published by EPA with metal concentrations in water and sediments. Then we tested the responses of biological variables to toxicity and other environmental conditions using the linear mixed effects models approach. We generated 32 models considering 24 different biological metrics and indices that were grouped in five levels. Taxonomic and abundance metrics were best predictor than functional or tolerance-based indexes. The strongest model was that which considered subfamily taxonomic resolution responding to Al_w and Cr_s.

Shedding light on the hidden world of subterranean fauna: A transdisciplinary research approach.

Subterranean environments contain a diverse and unique obligate fauna: either aquatic living in the groundwater or terrestrial living in voids above the water table. In the arid region of the western part of the Australian continent, a particularly rich subterranean fauna coincides with a concentration of natural resource extraction operations. Since the inclusion of subterranean fauna in assessments of environmental impact in the mid-1990s, taxonomic research in Australia on this group of mainly invertebrates has grown exponentially. However, remaining knowledge gaps continue to frustrate both environmental regulators and development proponents due to high uncertainty in the decision-making process. In early 2017, the Western Australian Biodiversity Science Institute was tasked with leading the development of a research program to improve on the current state of knowledge of subterranean fauna. To balance the diverse environmental, economic and social needs of a range of stakeholders, transdisciplinary principles were applied to program development. A clear consensus on five broad focus areas to progress include: (1) data consolidation; (2) resilience to disturbance; (3) survey and sampling protocols; (4) abiotic and biotic habitat requirements; and (5) species delineation. In the context of these focus areas; we describe the research program development, reviewing the status of knowledge within each focus area, and the research initiatives to close the gaps in knowledge. We argue that, by adopting a transdisciplinary approach, the likelihood of success of the research program, as measured by the effective translation and adoption of research findings, will be maximized. This review is timely given the ever-increasing demand on groundwater systems for water extraction worldwide. A holistic understanding of the influence of anthropogenic activities on these ecosystems, and the functional role of organisms within them, will help to ensure that their health is not compromised.

Amiskwia is a large Cambrian gnathiferan with complex gnathostomulid-like jaws.

Phylogenomic studies have greatly improved our understanding of the animal tree of life but the relationships of many clades remain ambiguous. Here we show that the rare soft-bodied animal Amiskwia from the Cambrian of Canada and China, which has variously been considered a chaetognath, a nemertine, allied to molluscs, or a problematica, is related to gnathiferans. New specimens from the Burgess Shale (British Columbia, Canada) preserve a complex pharyngeal jaw apparatus composed of a pair of elements with teeth most similar to gnathostomulids. Amiskwia demonstrates that primitive spiralians were large and unsegmented, had a coelom, and were probably active nekto-benthic scavengers or predators. Secondary simplification and miniaturisation events likely occurred in response to shifting ecologies and adaptations to specialised planktonic habitats.

The Temporal and Environmental Context of Early Animal Evolution: Considering All the Ingredients of an "Explosion".

Animals originated and evolved during a unique time in Earth history-the Neoproterozoic Era. This paper aims to discuss (1) when landmark events in early animal evolution occurred, and (2) the environmental context of these evolutionary milestones, and how such factors may have affected ecosystems and body plans. With respect to timing, molecular clock studies-utilizing a diversity of methodologies-agree that animal multicellularity had arisen by ∼800 million years ago (Ma) (Tonian period), the bilaterian body plan by ∼650 Ma (Cryogenian), and divergences between sister phyla occurred ∼560-540 Ma (late Ediacaran). Most purported Tonian and Cryogenian animal body fossils are unlikely to be correctly identified, but independent support for the presence of pre-Ediacaran animals is recorded by organic geochemical biomarkers produced by demosponges. This view of animal origins contrasts with data from the fossil record, and the taphonomic question of why animals were not preserved (if present) remains unresolved. Neoproterozoic environments demanding small, thin, body plans, and lower abundance/rarity in populations may have played a role. Considering environmental conditions, geochemical data suggest that animals evolved in a relatively low-oxygen ocean. Here, we present new analyses of sedimentary total organic carbon contents in shales suggesting that the Neoproterozoic ocean may also have had lower primary productivity-or at least lower quantities of organic carbon reaching the seafloor-compared with the Phanerozoic. Indeed, recent modeling efforts suggest that low primary productivity is an expected corollary of a low-O2 world. Combined with an inability to inhabit productive regions in a low-O2 ocean, earliest animal communities would likely have been more food limited than generally appreciated, impacting both ecosystem structure and organismal behavior. In light of this, we propose the "fire triangle" metaphor for environmental influences on early animal evolution. Moving toward consideration of all environmental aspects of the Cambrian radiation (fuel, heat, and oxidant) will ultimately lead to a more holistic view of the event.

Selective suppression of in situ proliferation of scyphozoan polyps by biofouling.

An increase in marine artificial constructions has been proposed as a major cause of jellyfish blooms, because these constructions provide additional substrates for organisms at the benthic stage (polyps), which proliferate asexually and release a large amount of free-swimming medusae. These hard surfaces are normally covered by fouling communities, the components of which have the potential to impede the proliferation of polyps. In this study, we report an in situ experiment of polyp survival of four large scyphozoan species found in East Asian marginal seas that were exposed to biofouling, a universal phenomenon occurring on marine artificial constructions. Our results showed that the polyps of three species (Nemopilema nomurai, Cyanea nozaki, and Rhopilema esculentum) attached to the artificial surfaces were completely eliminated by biofouling within 7-8months, and only those of moon jellyfish (Aurelia sp.1) in the upper layers could multiply on both artificial materials and other organisms (e.g., ascidians and bryozoans). Fouling-associated competition and predation and suppressed asexual reproduction of podocysts were observed to contribute to the loss of polyps. This study shows that the natural distribution of polyps is defined by the biofouling community that colonizes the surfaces of artificial constructions. Consequently, the contribution of marine constructions to jellyfish bloom is limited only to the ability of the jellyfish species to reproduce asexually through budding and inhabit solid surfaces of fouling organisms in addition to inhabiting original artificial materials. We anticipate that fragile polyps will colonize and proliferate in harsh environments that are deleterious to biofouling, and we propose special attention to polyps in antifouling practices for excluding the possibility that they occupy the available ecological space.

Genetic assessment of meiobenthic community composition and spatial distribution in coastal sediments along northern Gulf of Mexico.

Meiobenthic (meiofauna and micro-eukaryotes) organisms are important contributors to ecosystem functioning in aquatic environments through their roles in nutrient transport, sediment stability, and food web interactions. Despite their ecological importance, information pertaining to variation of these communities at various spatial and temporal scales is not widely known. Many studies in the Gulf of Mexico (GOM) have focused either on deep sea or continental shelf areas, while little attention has been paid to bays and coastal regions. Herein, we take a holistic approach by using high-throughput sequencing approaches to examine spatial variation in meiobenthic communities within Alabama bays and the coastal northern GOM region. Sediment samples were collected along three transects (Mississippi Sound: MS, FOCAL: FT, and Orange Beach: OB) from September 2010 to April 2012 and community composition was determined by metabarcoding the V9 hypervariable region of the nuclear18S rRNA gene. Results showed that Stramenopiles (diatoms), annelids, arthropods (copepods), and nematodes were the dominate groups within samples, while there was presence of other phyla throughout the dataset. Location played a larger role than time sampled in community composition. However, samples were collected over a short temporal scale. Samples clustered in reference to transect, with the most eastern transect (OB) having a distinct community composition in comparison to the other two transects (MS and FT). Communities also differed in reference to region (Bay versus Shelf). Bulk density and percent inorganic carbon were the only measured environmental factors that were correlated with community composition.

Chemoinformatic analysis as a tool for prioritization of trypanocidal marine derived lead compounds.

Marine trypanocidal natural products are, most often, reported with trypanocidal activity and selectivity against human cell lines. The triaging of hits requires a consideration of chemical tractability for drug development. We utilized a combined Lipinski's rule-of-five, chemical clustering and ChemGPS-NP principle analysis to analyze a set of 40 antitrypanosomal natural products for their drug like properties and chemical space. The analyses identified 16 chemical clusters with 11 well positioned within drug-like chemical space. This study demonstrated that our combined analysis can be used as an important strategy for prioritization of active marine natural products for further investigation.

Impact of mechanical deweeding on the phytophilous macroinvertebrate community of an eutrophic lake.

The aim of the study was to estimate the impact of mechanical deweeding on the community structure of phytophilous macroinvertebrates. The eutrophic lake selected for the study was Dal Lake in the Kashmir Himalayas. The dissolved nutrient concentration was found to be highest in August and September, i.e., nitrates-nitrogen (513 µg l(-l)) and total phosphorus (685 µg l(-l)). During the period of investigation, a total of 22 macroinvertebrate taxa were recorded which belonged to phylum Arthropoda, Mollusca, and Annelida. The samples were collected with the help of a composite Gerking frame box and grappler. Mechanical deweeding had a profound impact on the population density of phylum Mollusca and Arthropoda followed by Annelida. However, family Tubificidae was not influenced by deweeding, as the harvester only trimmed the vegetation, and these organisms were recorded in the sediment of the lake. On average, the reference site had higher density of macroinvertebrates as compared to deweeded areas. The abundance of macroinvertebrates decreased from 200 ind. (individuals) m(-2) in the reference site to 51 ind. m(-2) in the deweeded site as a result of weed removal. Species richness and composition of major macroinvertebrates in harvested and unharvested areas of the lake were also dissimilar as portrayed by biotic indices vis-à-vis Shannon diversity index, evenness index, and Simpson index.

Relations between macroinvertebrates, nutrients, and water quality criteria in wadeable streams of Maryland, USA.

In an ongoing effort to propose biologically protective nutrient criteria, we examined how total nitrogen (TN) and its forms were associated with macroinvertebrate communities in wadeable streams of Maryland. Taxonomic and functional metrics of an index of biological integrity (IBI) were significantly associated with multiple nutrient measures; however, the highest correlations with nutrients were for ammonia-N and nitrite-N and among macroinvertebrate measures were for Beck's Biotic Index and its metrics. Since IBI metrics showed comparatively less association, we evaluated how macroinvertebrate taxa related to proposed nutrient criteria previously derived for those same streams instead of developing nutrient-biology thresholds. We identified one tolerant and three intolerant taxa whose occurrence appeared related to a TN benchmark. Individually, these taxa poorly indicated whether streams exceeded the benchmark, but combining taxa notably improved classification rates. We then extracted major physiochemical gradients using principal components analysis to develop models that assessed their influence on nutrient indicator taxa. The response of intolerant taxa was predominantly influenced by a nutrient-forest cover gradient. In contrast, habitat quality had a greater effect on tolerant taxa. When taxa were aggregated into a nutrient sensitive index, the response was primarily influenced by the nutrient-forest gradient. Multiple lines of evidence highlight the effects of excessive nutrients in streams on macroinvertebrate communities and taxa in Maryland, whose loss may not be reflected in metrics that form the basis of biological criteria. Refinement of indicator taxa and a nutrient-sensitive index is warranted before thresholds in aquatic life to water quality are quantified.

Taxonomical outlines of bio-diversity of Karnataka in a 14th century Kannada toxicology text Khagendra Mani Darpana.

Origin of ancient Indian toxicology can be dated back to vedic literature. Toxins of both animate and inanimate world were very well understood during the era. Rig and Atharva vedic texts describe such details. After classifying such toxins, Charaka Samhitha, the basic literature of Indian Medicine used gold and ghee as panaceas to counter act them. Ayurveda considers toxicology as one among the eight specialized branches of medical wisdom. Unfortunately, the available literature on this is very limited. Moreover, they have been discussed briefly in Charaka and Sushrutha Samhitha. Mangarasa I, a Jain scholar who lived on the foothills of the Western Ghats, in Southern India in 1350 A.D., felt this vacuum and composed an independent, elaborate Kannada text on toxicology. His less known text Khagendra Mani Darpana (KMD) is the first ever documented complete text on toxicology in the world. Medieval Indian wisdom on plant and animal diversities are very well reflected in this unique toxicological text. Centuries past to Linnean era, KMD gives vivid descriptions on zoological and botanical diversities of the time. This astonishing fact is an evidence of our ancestor's curiosities about the nature around them. A critical overview of the bio-diversity described in KMD text is discussed in this paper.

Deep-sea benthic footprint of the deepwater horizon blowout.

The Deepwater Horizon (DWH) accident in the northern Gulf of Mexico occurred on April 20, 2010 at a water depth of 1525 meters, and a deep-sea plume was detected within one month. Oil contacted and persisted in parts of the bottom of the deep-sea in the Gulf of Mexico. As part of the response to the accident, monitoring cruises were deployed in fall 2010 to measure potential impacts on the two main soft-bottom benthic invertebrate groups: macrofauna and meiofauna. Sediment was collected using a multicorer so that samples for chemical, physical and biological analyses could be taken simultaneously and analyzed using multivariate methods. The footprint of the oil spill was identified by creating a new variable with principal components analysis where the first factor was indicative of the oil spill impacts and this new variable mapped in a geographic information system to identify the area of the oil spill footprint. The most severe relative reduction of faunal abundance and diversity extended to 3 km from the wellhead in all directions covering an area about 24 km(2). Moderate impacts were observed up to 17 km towards the southwest and 8.5 km towards the northeast of the wellhead, covering an area 148 km(2). Benthic effects were correlated to total petroleum hydrocarbon, polycyclic aromatic hydrocarbons and barium concentrations, and distance to the wellhead; but not distance to hydrocarbon seeps. Thus, benthic effects are more likely due to the oil spill, and not natural hydrocarbon seepage. Recovery rates in the deep sea are likely to be slow, on the order of decades or longer.

Initial impacts of the Hebei Spirit oil spill on the sandy beach macrobenthic community west coast of Korea.

Petroleum hydrocarbon contamination and macrobenthos in the sandy tidal flats of Taean were monitored for 1 year to assess the impacts of Hebei Spirit oil on the macrobenthic community. A total of 207 macrobenthic fauna was collected, and the mean density and biomass of macrobenthic fauna continued to decrease until 12 months after the oil spill, but macrobenthic density at the most heavily affected sites increased by about twofold. In January 2008, the dominant species occurred at very low densities in strongly affected sites. The macrobenthic communities differed between oil-affected and unaffected sites. In particular, differences in community structure at Mallipo beach were larger than those at Shinduri. We suggest that long-term monitoring is needed to assess the specific effects of oil pollution on the sandy intertidal macrobenthic community.

Recovery of benthic megafauna from anthropogenic disturbance at a hydrocarbon drilling well (380 m depth in the Norwegian Sea).

Recovery from disturbance in deep water is poorly understood, but as anthropogenic impacts increase in deeper water it is important to quantify the process. Exploratory hydrocarbon drilling causes physical disturbance, smothering the seabed near the well. Video transects obtained by remotely operated vehicles were used to assess the change in invertebrate megafaunal density and diversity caused by drilling a well at 380 m depth in the Norwegian Sea in 2006. Transects were carried out one day before drilling commenced and 27 days, 76 days, and three years later. A background survey, further from the well, was also carried out in 2009. Porifera (45% of observations) and Cnidaria (40%) dominated the megafauna. Porifera accounted for 94% of hard-substratum organisms and cnidarians (Pennatulacea) dominated on the soft sediment (78%). Twenty seven and 76 days after drilling commenced, drill cuttings were visible, extending over 100 m from the well. In this area there were low invertebrate megafaunal densities (0.08 and 0.10 individuals m(-2)) in comparison to pre-drill conditions (0.21 individuals m(-2)). Three years later the visible extent of the cuttings had reduced, reaching 60 m from the well. Within this area the megafaunal density (0.05 individuals m(-2)) was lower than pre-drill and reference transects (0.23 individuals m(-2)). There was a significant increase in total megafaunal invertebrate densities with both distance from drilling and time since drilling although no significant interaction. Beyond the visible disturbance there were similar megafaunal densities (0.14 individuals m(-2)) to pre-drilling and background surveys. Species richness, Shannon-Weiner diversity and multivariate techniques showed similar patterns to density. At this site the effects of exploratory drilling on megafaunal invertebrate density and diversity seem confined to the extent of the visible cuttings pile. However, elevated Barium concentration and reduced sediment grain size suggest persistence of disturbance for three years, with unclear consequences for other components of the benthic fauna.

Large-scale utilization of water hyacinth for nutrient removal in Lake Dianchi in China: the effects on the water quality, macrozoobenthos and zooplankton.

An ecological engineering project using water hyacinth for nutrient removal was performed in Baishan Bay of a large shallow eutrophic lake, Lake Dianchi in China. In the present study, a systematic survey of water quality, macrozoobenthos and zooplankton inside (IWH), around (AWH) and far away (FWH) water hyacinth mats was conducted in Baishan Bay from August to October 2010. The results showed that the water quality significantly improved at AWH area. Concentrations of nitrogen and phosphorus were lower and transparency was higher at AWH area than those in IWH and FWH areas. Total densities, dominant species densities, and biodiversity indexes of macrozoobenthos and cladocerans as well as copepods did not differ (P>0.05) among each other in all three areas. It was significantly (P<0.05) different for those of rotifers at IWH area compared to those in AWH and FWH areas. The results might suggest a tremendous potential for the utilization of water hyacinth in the eutrophic lake like Lake Dianchi for nutrients removal.

[Impacts of urbanization on the water quality and macrobenthos community structure of the tributaries in middle reach of Qiantang River, East China].

The 59 1st-3rd order tributaries in the middle reach of Qiantang River are negatively affected by different intensities of urbanization. In April 2010, an investigation was conducted on the water bodies' physical and chemical properties and macrobenthos communities of the tributaries, with the relationships between the tributaries' water quality and biological communities and the percentage of ground surface impervious area (PIA), an indicator of urbanization intensity. The Spearman correlation analysis showed that the water bodies' NH(4+)-N, PO4(3-)-P, TP, COD(Mn), conductivity, width, depth, and fine sand/silt ratio were positively correlated with PIA, and negatively correlated with forest land area. The fitted nonlinear regression equations revealed that all the test macro-benthic invertebrate's parameters had significant relationships with PIA, of which, the total number of taxa, Shannon diversity index, richness index, EPT (%), predators (%), shredders (%), filterers (%) and scrapers (%) were negatively correlated to PIA but positively correlated to forest land area, and the BI, collectors (%), tolerance taxa (%) and oligochaeta (%) were positively correlated to the PIA. Our study indicated that under the impact of urbanization, these tributaries presented the common features of degradation, i. e., high concentrations of nitrogen and phosphorus, degradation of physical habitat, disappearance of pollution-sensitive macro-benthic invertebrate species, and dramatic increase of pollution-tolerant species individuals.

Calibrating the end-Permian mass extinction.

The end-Permian mass extinction was the most severe biodiversity crisis in Earth history. To better constrain the timing, and ultimately the causes of this event, we collected a suite of geochronologic, isotopic, and biostratigraphic data on several well-preserved sedimentary sections in South China. High-precision U-Pb dating reveals that the extinction peak occurred just before 252.28 ± 0.08 million years ago, after a decline of 2 per mil (‰) in δ(13)C over 90,000 years, and coincided with a δ(13)C excursion of -5‰ that is estimated to have lasted ≤20,000 years. The extinction interval was less than 200,000 years and synchronous in marine and terrestrial realms; associated charcoal-rich and soot-bearing layers indicate widespread wildfires on land. A massive release of thermogenic carbon dioxide and/or methane may have caused the catastrophic extinction.

[Impact of Mikania micrantha invasion on soil meso- and micro-invertebrate community structure].

Mikania micrantha, a notorious exotic weed of Asteraceae family, has invaded successfully in southern China, and caused serious damages to native ecosystems. In this paper, a field survey was conducted in the Huolushan Forest Park of Guangzhou, China, aimed to understand the impact of M. micrantha invasion on the soil meso- and micro-invertebrate community. Three sampling sites were installed, including M. micrantha-invaded site, ecotone, and native vegetation site. Through four samplings in 2009, a total of 5206 soil meso- and micro-invertebrate individuals were collected, belonging to 4 phyla, 10 classes, and 19 orders, among which, Nematoda was the dominant group, and Acarina, Collembolan, and Rotifera were the common groups. M. micrantha invasion altered the characteristics of soil meso- and micro-invertebrate community structure. Compared with those at the other two sampling sites, the numbers of total individuals, Nematoda, and Acarina at M. micrantha-invaded site increased significantly, but the groups of soil meso- and micro-invertebrates had less change. At M. micrantha-invaded site, the density-group index (DG) of soil meso- and micro-invertebrates was significantly higher, Margalef richness index (D) and Simpson dominance index (C) tended to ascend, but Pielou evenness index (E) and Shannon index (H') tended to descend. The similarity coefficient of soil meso- and micro-invertebrate community between M. micrantha-invaded site and ecotone was higher than that between M. micrantha-invaded site and native vegetation site. The changes of local climate conditions, plant litters, root secretions, and soil physical-chemical properties caused by M. micrantha invasion could be the major contributing factors that altered the community structure of soil meso- and micro-invertebrates at M. micrantha-invaded site.

[Estimation of river nutrients thresholds based on benthic macroinvertebrate assemblages: a case study in the upper reaches of Xitiao Stream in Zhejiang, China].

Water eutrophication is a global problem, and one of the major environmental problems in China. At present, its studies in China are mainly focused on lakes and reservoirs, whereas a few on rivers. Based on the stress-response of benthic macroinvertebrate assemblages to water nutrients, we used the nonparametric deviance reduction (change point analysis) to compute the breakpoints of nutrients concentrations, in the upper reaches of Xitiao Stream in Zhejiang. The results indicated that the breakpoints of total nitrogen (TN) and total phosphors (TP) were 1.409 mg x L(-1) and 0.033-0.035 mg x L(-1), respectively. The TN and TP concentrations at reference sites were lower, while those at urban sewage- polluted sites were higher than the thresholds. In latter case, a serious degradation of benthic macroinvertebrates assemblages could be induced. To establish water nutrients criteria with relation to aquatic organisms would make the biological monitoring play a full role in water management, and provide scientific data to estimate the total maximum daily load (TMDL) of TN and TP in water body.

[Effects of grassland restoration from cropland on soil macrofaunal community in Wuchuan County, Inner Mongolia].

By the method of hand-sorting, and using the indices individual number, group number, and biodiversity, the changes in the soil macrofaunal community under the grassland restoration from cropland in Wuchuan County, Inner Mongolia were investigated. A total of 1479 soil macrofauna belonging to 3 classes, 7 orders and 41 families were captured. After the grassland restoration from cropland, the group number, individual number, and biomass of soil macrofauna all had an increasing trend, and the biodiversity of soil macrofaunal community reflected by D(Ma) and DG increased significantly. However, due to the short term of cropland rehabilitation, the Shannon-Wiener index H' and the Pielou evenness index E of the soil microfaunal community in grassland were not higher than those in cropland. Different soil macrofaunal groups had different responses to the grassland restoration from cropland. The preferable approaches for the grassland restoration from cropland were planting Medicago sativa or planting Medicago sativa + Artemisia sp.

Impact of fish farming on foraminiferal community, Drvenik Veliki Island, Adriatic Sea, Croatia.

This study examined the impact of fish farming on foraminiferal communities in the Adriatic coastal zone. Samples were taken directly beneath the farm, near the edge of the farm, and at a reference station away from the farm. The foraminiferal community near the farm is characterized by Epistominella exigua, Globocassidulina subglobosa, Haynesina germanica and the genera Elphidium, Bulimina and Brizalina. These foraminiferal species are less abundant seaward. Asterigerinata mamilla, Neoconorbina terquemi and genus Cibicides are almost absent below the cages. Total phosphorus (TP) and total nitrogen (TN) in the sediments decrease with distance from the cages. The abundances of E. exigua, G. subglobosa, H. germanica and the genera Elphidium, Bulimina and Brizalina are correlated with TP and TN, indicating their dependence on nutrient input. The absence of A. mamilla, N. terquemi and the genus Cibicides below the cages is a due to a degraded Posidonia community. According to our study, foraminiferal community composition can be used as indicator of organic enrichment caused by fish farm activities.